A siege draws Roman armies into open battle

The siege remains in place to draw Roman formations toward it instead of rushing the walls. When the garrison sorties, the fight moves outside the defenses, where the walls no longer multiply the defender's strength. Missile troops form the forward lines while massed cavalry exploits an enemy commander who has moved away from support and become trapped against his own fortifications. This game situation shows how a siege can shape where relief forces assemble and whether the decisive battle occurs in open ground. It also warns against assuming an opponent is weak while forces are concentrating nearby.